loebell



Feb. 3, 1931. H. o. LOEBELL MANUFACTURE COMBUSTIBLE GAS Filed Ma'rh 15 3 Sheets- Sheet l Nw Nw s Feb- 3, 1931- H. o. LOEBELL 1,790,24

MNUFACTURE OF COMBUSTIBLE GAS Filed March 15, 1924 'sneets-sneet 2 Feb- 3, 19.31- H. o. LOEBELL. 1,790,824

MANUFACTURE OF COMBUSTIBLE GAS Filed March 15, 1924` 3 Sheets-sheet 5 Patented Feb. 3, 1931 UNITED s'rn'rasv PATENT OFFICE I HENRY O. LOEBELL, OF NEW YORK, N. Y., ASSIGNOB'TO HENRY DOHERTY, Ol'

NEW YORK, N. Y.

'IM-ANUFACTUBE OF COMBUSTIBLE Application med umn 15, 1924. serial no. 699,419.

This invention relates to the manufacture 'of combustible gas, and more particularly to a method of and apparatus for making water' gas.

The gas making process of the present invention is of the same type of gas making process as that which is shown and described in my co-.pending application, Serial No. 4s1,195 ,f1ed June 29, 1921.

The method of making water gas as described in the above application may be briefly outlined as follows: A mixturev of coal and coke, in which the coke may vary from one-fourth to one-half the amount of coal, is continuously passed downwardly ina column. through a shaft generator., To generate gas a high temperature zone is maintained in the mid-portion of the fuel column by intermittently blasting air therethrough. The blast air is introduced into the column below two suspended arches positioned on opposite sides of the generator shaft, and after passing downwardly through the fuel in the mid-portion of the column, the blast gases are removed beneath another pair of suspended arches which face each other and are built at right angles to the two blast arches. The two sets of arches are vertically separated a substantial distance, so that the high temperature zone is comparatively large, and the blast gases after passing through it contain a comparatively high percentage of carbon monoxide and hydrogen. The coal in the upper part of the generator is distilled, forming coal gas and coke, and the coke formed, together with that admitted with the charge, is treated intermittently with 'steam to make blue water gas.

The primary object of the presentV inven'- tion is to provide a method of and apparatus for making combustible gas by which the gasifying zone of a fuel bed may be so distributed and controlled that larger volumes of fuel can be gasiied per unit of time than has been possible heretofore.

In accordance with this object, one feature of the invention contemplates the provision of additional nostril openings into the gas making zoneof the shaft, and the arrange,- ment of these openings and the operation of the path of the blast air used to maintain a high temperature gasifyin zone inthe fuel 'column is held comparative y short in length, -while the path of the make Asteam is made long, so that the blast gases are permitted to remove only a minimum amount of heat from the gasifying zone, while the make water gases are correspondingly enriched in vheat- 1ng value by allowing the make steam a comparatively ong time contact with the incandescent fuel in the gasifying'zone.

- Another object of the invention is to provide a method of and apparatus for making water gas by which the temperatures in the fuel bed may be so controlled as to substantially prevent damage to the ap ratus. so With' this obj ect in view anot er feature of the present invention contemplates the provision of means whereb the point of introduction of the blast a1r and ofthe, make steam, and the point of removal of the blast l gases, may be alternated and interchanged at frequent intervals.

With these and other objects and features in view, the invention comprises the improved method of and apparatus for making combustible gas hereinafter described and par ticularly .defined in the claims.

and their connections, embodying the preferred form of the invention.

Fig. 2 is a top plan view, partly in section, of the apparatus shown in Fig. 1; and

Fig. 3 is a side elevation, partly in section, i); the apparatus taken on the line 3 3 of The method of and apparatus for making gas which embodies the preferred form of the present invention constitutes an improvement in the manufacture of the same type of combustible gas as that described in the aforementioned application, which is essentially a blue water gas enriched with coal as. The method of making this gas accordlng to the in passing el, such as a mixture of coal and coke, downwardly in a column through a shaft generator, and subjecting the fuel in the columnto a series of heat treatments during its passage throu h the generator whereby itis either partial y or completely decomposed into combustible gas and ash. A high temperature zone is maintained in the mid;

ortion of the column by intermittently lasting air either downward radially or upward corradially through the fuel column to raise the temperature of the fuel to incandescence, and between blasting operations steam is passed upwardly through this high temperature zone, reacting with the carbon of the fuel lto form water gas. The water gas thus formed is passed upwardly through the fuel in the upper part of the column, giving up its sensible heat to thedescending fuel and driving off the volatile products from the coal. The enriched mixture of comparatively cool watergas and volatile products of .the coal distillation is withdrawn from the top ofthe shaft, and after passing through condensers, -tar scrubbers, washers, and purifiers is conducted to a gas holder. The blast gases are removed directly from the high temperature zone through either an axial or a peripheral offtake,nand their sensible and potential heat is recovered in waste heat. boilers and in regenerators and isreturned to the lhigh temperature zone by the blast air and the make steam, which are preheated in the regenerator before being introduced into the unburned fuel column. The fuel and ash in the lower ortion of the column, after passing the igh temperature zone, is quenched by a jet of water or steam which passes upwardly through this part of the column toward the high temperature zone,

and the comparatively cool mixture of fuel and ash is discharged from the bottom of the Icolumn and any unconsumed coke therein is separated and returned to the top to be recharged in `admixture with fresh coal.

The preferred form of making gas may be carried out in the'appa'ratus shown in the drawings as follows:

A mixture of coal and coke is placed in a resent invention i consists briefly.

hopper 10, Figs. 1 and-3, and is periodically i ing gates 12 are of the hollow cone air tighttype, and are operated continuously. A reference is hereby made to my copending applicati on, Serial No. 141,047, filed October 12, 1926, for a more com lete descriptionl of the construction and mo e of operation of these charging gates. The fuel is supported in a column and is advanced lsubstantially continuously and without obstruction downwardly through the shaft. In its passage through the shaft the fuel' first enters an annularheating and fuel carbonizing zone 15 in the upper portion of the shaft around an axially supported superheater 16. From the fuel carbonizing zone it passes into a high temperature zone 17 in the mid-portion of the shaft, lyingsubstantially between nostril 18 of the axiallysupported central tube superheater and two circumferential horizontal wall extensions V20 and 22, where it is'subiected to a blast of preheated air. From the igh temperature zone the fuel passes into a cooling zone 23 in the lower portion of the shaft, where it is cooled by contact with ya countercurrent circuit of steam. The column of fuel is supported in the shaft, as well as being agitated and advanced through the shaft, by a discharging apparatus positioned in the bottom. of the shaft. This apparatus consists essentially in a revolving eccentricl patentto Wonnin-g, No. 1,768,945, issued July g 1, 1930, for a more complete description of a discharging apparatus of this type. The air for blasting is introduced through Va. pipe 27, see Fig. 2, into a water vaporizing element 28 of one of a pair of regenerators 30 or 32. When air is passing through the regenerators it enters the top of the vaporizing element 28 and immediately comes in contact with previously heated refractory brick positioned within the vaporizing element. After the air passes through the vaporizing element it Hows through a cross-connection 34 into a chamber 36. Each of the regenerators 30 and 32 embodies a vaporizing element 28Vv and a combustion chamber 36 with a cross connection 34 see Fig. 2). Likewise each of the regenerators 30fand 32 has a blast connection with the shaft through two nostrils 38 and 39 positioned on opposite sides of the shaft and also' with` the central tube 116 through a conduit 40 and valve 41, see Figs 2 and 3, so that air may pass from the chamber 36 through either of the nostrils 38 or 39 or throughthe tube 16 and nostril 18 into the fuel column. The nostril 38 opens into the shaft immediately below the flat circumferentialwall extension 20 andthe nostril 39 opens immediately below the wall'extension 22. Each of these nostrils has a baille 37 in front of its opening, so that the air entering the fuel column is diverted to follow circumferential paths beneath the horizontal wall exteusions`20 or 22 in both directions from the blast nostril, and is thus introduced into the fuel column around its whole periphery.

Two waste heat steam boilers 42 and 44 have exhaust gas connections with the nostrils 38 and 39 and with the central tube 16, and these boilers also have 4exhaust gas connections with the regenerators 30 and 32. Thus, when air from the regenerator 30 is introduced into the fuel .column through one of the nostrils 18, 38, or 39, it may follow a diagonal course either downwardly or upwardly as the case may be, and the blast products or blast gases may leave the col-` umn through one of the other nostrils. However, these blast gases are preferably removed through the nostril 18 and the central tube,

one or'both of lnostrils 38 and 39 being simultaneously used for introducing blast air. After passing through either of the waste heat .boilers 42 or 44 these blast gases are conducted to the chamber -36 of the regenerator 32. A large part of the sensible heat of the blast gases is absorbed in the waste heat boilers, where it is utilized in generating steam.` Most of the remaining potential heat in the blast gases is recovered by burning them inthe chambers 36, and storing the heat of com' top of the vaporizing elements.

bustion `in the refractory materials filling the superheating and vaporiz'ing elements of the regenerators, so that waste gases escape substantially cool through an outlet 46 at the At the time the regenera-tor 30 is being used for preheating the blast lair, the regenerator 32 together with one of the wasteheat boilers is used for absorbing the heat of the blast gases after they have passed through the fuel bed. Since the path of the blast air through the high temperature blast zone in the shaft is sometimes comparatively long, the blast gases at the time they leave the shaft may contain a comparatively hig'h ,percentage of carbon monoxide, and itis necessary to burn these gases in order to re` cover their potential heat. In order to burn the blast gases after they have been cooled in one of the waste heat boilers, preheated air is introduced into the chamber 36 of the regenerator 32 through a pipe 48, see Fig. 2. The chamber 36 affords a comparatively,V large space in which to promote the combustion of the blast gases, and the hot products of combustion are then passed into the refractory linings of the superheating element 34 and vaporizing element 28 of the regenerator. When the regenerator 32 has acted as a heat storage element during one blast operation, during the next blast operation it acts as the air preheating element, and the regenerator 30 acts as the heat storage element. At this time the direction of passage of the air and riphery of the fuel charge supported therein. The blast air may alternatively be introduced into the generator through the nostril 38 and pass from circumferential passage 4 9 through the fuel in zone 17 to the axial nostril opening 18. e In accordance with these methods of circulation the air and blast gases will follow alternatively .either a radial or a corradial course. as the case may be and be removed either peripherally or axially through the passage 49 and nostril 38, or through the nostril 18 and the central tube16, respectively, see Fig. 3. By forcing the blast air to take a substantially direct ath between the nostril 18- and the cir-cum erential passage n 49. The air is limited to a very short time contact with the incandescent fuel in its path,

and the blast gases will remove a muc-h small- Verl amount of heat from the fuel bed than would be the case if their contact time and path vwere, longer. The potential heating value of the blast gases when operating according to this method is much smaller than that of the blast gases ordinarily treated, and the heat can be efficiently recovered and utilized, which is not always thecase when'the blast gases have a higher potential heating value. Of course when thepath of the blast gases is shortened, the extent of the high temperature gasifying zone ofthe fuel column is correspondinglyshortened. In order to maintain a high gas making capacity the high temperature zone must be comparatively large and at a more or less uniformly high temperature.l To obtain this result it is necessary at times to extend the path of the blast air and blast gases to a circumferential passage 50 beneath the horizontal wall extension 22 between the inner lining of the shaft and the outer periphery 'of the fuel charge, 'see'Fig 1. Thus blast air may be introduced into the column either through the nostrils 18 or 38 and the blast gases will be removed through the circumferential passage 50 and the nostril 39. The blast air may b'e introduced at intervals through .the nostril 39 and passagel 50, and they blast gases will then be removedl through the nostril 18 and the central otake, or else through the circumy ferential passage 49 and the nostril 38.

The nostril 38 is connected through the Y- vconnection 51, provided with hot valves 52 and 53, to the waste heat boilers 42 and 44, see Fig. 2. The nostril 39 is likewise connected through the Y-connection 54, having valves and 56, to the combustion chambersl 36 of the two regenerators 30 and 32. The arms of the Y-connections 51 and 54 are each fitted with a T 57. A Y-connection 58 has its arms connected to the arms of the Y-connection 54 by other Ts 57, and lies in the same horizontal plane as the Y-connection 54. Likewise, a Y connection 59 has its arms similarly connected to the arms of the Y connection 51. The nostril 38 is connected through a conduit 60, having a valve 62, and through an extension conduit 64, a T 65, and a'iiange connection 66, see Fig. 3, with the Y-connection 58, and thus through Valves 67 and 68 in its arms to the two regenerators 30 and 32. Likewise the nostril 39 is connected through a conduit 70, having a valve 72v (Fig. 2), with the Y- connection 59, and thus through valves 74 and 76 in the arms of said Y with the two waste heat boilers 42 and 44.

When one of the'hot valves 55 or 56 Jis opened blast air from one of the corresponding regenerators 30 or 32 will enter the shaft vthrough the nostril 39, but when valves 55 and 56 are both closed and one of valves 67 or 68 is opened, air from the corresponding regenerator will pass through the conduit into the shaft through the nostril 38. When the blast air is introduced into the shaft from regenerator 30 through the Y-connection 54, valve 55, and through the nostril 39, it follows essentially a diagonal course upwardly through the fuel column, and the producer gases formed bythe reaction of the air and steam with the incandescent fuel are dr'awn off through one of the nostrils 18 or 38. These blast gases may be taken from -the nostril 38 directly to regenerator 32 through the conduit 60, valve 62, extension 64 and valve 68, the other valves 67 and 56' in the two Y-connections 54 and 58 being closed to prevent the mixing of blast :air and blast gases. When the valve 62 in the conduit 60 is closed and one of hot valves 52 or 53 in the Y-connection 51 is opened, the blast gases will enter the corresponding waste heat boiler. When the blast gases are removed through the nostril 18 and the central tube 16, they are passed through a conduit 77 and a hot valve 78 into the Y-connection 59 and thence to either of the waste heat boilers 42 0r 44. If the blast gases are allowed to enter` the boiler 42 through the nostril 38 and valve 5 2, for instance, on their passage through the boiler they will be cooled to a comparatively low temperature by a heat transfer with the through a conduit 83 into the conduit 60 and thence through the extension 64 and valve 68 into the regenerator 32, as in the previousease. When the hot blast gases are returned' to the regenerator 32 directly from the nostril 38, as in the rst case cited, they are burned by introducing' a blast of cool air into the top of the combustion chamber 36 through the pipe 48, by openin both valves 88 and 90, while keeping the va ve 86 closed. Y There are many advantages to be gained by altering the direction ofv flow and vthe place of introduction of the hot blast air at frequent intervals during the blasting operation. If the blast air is at all times lntroduced into the lower portion of the hi h temperature zone of the fuel column, or example, and if after following an upward course, the blast gases are always removed from the upper portion of the high temperature zone, it will be found impossible to maintain a uniformly high temperature throughout the extent, of this so-called high temperature zone. Thus while primarily the reaction which takes place between the heated fuel and the blast air is exothermic, resulting in the formation of carbon dioxide, as this carbon dioxide travels through the body ofv heated fuel toward the gas offtake it is broken down by a second reaction with the carbon of the fuel, forming carbon monoxide, and this secondary reaction is endothermic in nature. The result is that while veryhigh temperatures may obtain in the lower portion ofthe high temperature zone adjacent the blast inlet, the temperatures will gradually drop as the blast gases approach the upper portion of this zone, so that there is a very considerable temperature differential between the lower and upper extremities of the high temperature zone 1n this case. Since the hottest portion of this high temperature zone lies immediately adjacent to the blast 'air inlet, and since the, use of temperatures above certain limits in this section is very deleterious to the refractory material forming the lining and wall extensions of the generator, it is usually impracticable to kee the temperature ofthis section high enougli to hold the upper part of the blast zone at an efiicient gas making temperature. For this reasonthe volume of the high temperature making operation is limitediin extent, and the gas making capacity andthe efficiency of the apparatus is lowered proportionately. Therefore, by alternately introducing the zone which is eflicient for use in the gasl blast air at the top and bottom portions of the high temperature zone, and passing the blast ases either upward or downward diagona ly through this zone, the temperature differential between the upper and lower portions of the zone is practically eliminated. Moreover, the temperatures throughout the whole extent of the high temperature zone may be held well above the lower limit for eilicient gas making without using temperatures which are deleterious to the generator linin in any part, and by maintaining a uniform y eiiicient gas making temperature throughout the whole extent of this zone the gas making lefficiency and capacity of the apparatus is greatly increased. i

If during part of the blasting operation the blast air has been introduced from the regenerator into the shaft through the nostril 39, as outlined above, during the next blasting period it will be advisable to heat the blast air in regenerator 32 and introduce the preheated air into the shaft either through the nostril 18 or through'the nostril 38, so

that it will follow a downward path through the column of fuel, opposite in direction to the path taken by the blast gases in the case previously discussed. In this case the preeatedair from the regenerator passes through the Y-connection 58 and valve. 68,

the extension 64, conduit 60, and valve 62 into the shaft through the nostril 38, or preferably through the conduit 40, which is connected to the T 65, see Fig. 2, and past valve 41 into the shaft through the central tube nostril 18. The blast gases pass out of the shaft through the nostril 39, and may be taken directly to the regenerator 30 by opening valve 55, valves 56 and 67 remaining closed.

Preferably, however, the blast gases are passed from the nostril 39 through the conduit and past hot valve 72 to the Y-connection 59, and thence through one of the two valves 74 or 76 into the corresponding waste heat boiler. When the blast ases are introduced into boiler 44, valve 76 is opened, while valves 74 and 53 are closed. The cooled blast gases after passing through the boiler are removed and may be taken to a storage holder through a pipe 92 and valve 94, but generally' they are returned through a valve 96 and a pipe 98, and through connections 99, 100, and one arm of a `U-shaped manifold 102 and valve 104, into the left arm of the Y-connection 54 at the T 57 and thence into regenerator 30 to be burned therein. When using this circuit the valve 94 in the pipe 92 is closed, as are also valves 106 in the conduit 98 and 108 in the other arm of the U-connection 102, see Fig. 3. The valves 81 and 82 in the conduit 83 and valves 55, 67 and 56 in the Y-connections 54 and 58 are also closed when using this circuit. When the hot blast gases from the nostril 39 are passed through the conduit 70 and valve 74 in the Y-eonnecators 30 and 32.

tion 59 into the waste heat boiler 42, they are returned to the regenerator 30 by passing them through the conduit 83 and valve 81, thence throu h a pipe 109 into the connec tions 100 and U-connection 102, and thence to the regenerator as in the previous case. When using this circuit the valves 76 and 52 in the Y-connections 59 and 51 and the valves in pipe 79,82, 96'v and 106 in the conduit 98, 108 in the U-coiinection 102, and 55, 67 and 56 in the arms of the Ys 54 and 58 are all closed.

As mentioned heretofore, a great part of I the potential heat carried by the hot blast gases is recovered in theregenerators, and these gases are comparatively cool when they are removed through the outlet stacks 46. Occasionally, however, it may be found that these gases still carry suiiicient sensible heat to make a further cooling treatment profitable. For this purpose valves 110 are placed in the stacks 46 `and two pipes 112 provided with valves 114 are connected to the stacks below the valves 110, so that the products of combustion 'from the regenerator may be taken through the pi es 112 to be further cooled in feed waterA eaters or other types of -heat economizers.

During the blasting period the direction of air blast may be reversed as often as may be found necessary in order to maintain a uniformly high temperature throughout the high temperature zone of the fuel column. Afteruthe blastngoperation has continued for a sutiieiently long period to develop the uniform temperature .of incandescence required in this zone, the air is cut off and water is admitted to the top of the regenerator-vaporizing elements 28 through pipes 116 and distributing means positioned in the top of the vaporizing elements. In case the vaporizing elements of the regenerators are not heated to a sufficiently high temperature to vaporize the water, steam from thev wasteV heat boilers 42 and 44 is admitted to the vaporizing elements through pipes 118, 120 and 122, see Fig. 2. By these connections either steam or water, or a mixture of steam and water may be admitted to the top of the vaporizing elements 28. The water is vaporized by contact with the refractory material in the vapori'zers, and the steam formed therein passes through the c ross connection 34 into the chambers 36 of both the regener- A part of the steam passing through the chambers 36 enters the shaft 14 through the valves 55 and 56 and the nostril 39, and passes into the fuel column below the circumferential wall extension 22, Fig. 1,

via circumferential passage 50. Another part of the steamifromvthe regeneratorchamber 36 is passed through the valves 67 and 68 into the conduit 40 and isled through this conduit past the valve 41 into the top of the central tubesuper-heater 16 and thence into the fuel column through the axial nostril 18, see Fig. 3. Steam from the waste heat boilers is conducted through pipes 124 and a stop valve into a distributing chamber 125 in the top of the superheater 16, and circulates through tubes 126 between the lining of the Y nozzle 127 having a stop valve with outside control, and throughsmall openings in the inner wall of the collecting chamber, supple' inenting the supply of steam from the regen erators.

B all of these arrangements the heat of com ustion and sensible heat of the blast gases is conserved in supplying the heat of evaporation and the superheat ofthe steam used in water gas making. As a rule, no steam is admitted through the nostril 38. The steam introduced through the nostril 18 and through the circumferential opening below the wall extension 22 all enters the high temperature zone 17, and the water gas formed in the high temperature zone, together with any excess steam, passes upwardly through the fuel column and leaves the to of the shaft 14 through a circumferential oiftake 1.28 and foul gas main 129. The hot water gases after leaving the high temperature zone transfer their sensible heat to the fuel in the upper parts of the column, furnishing enough heat to carbonize the coal in the column above the high temperature zone. The carbonization of the fuel 1n the column above the high temperature zone is carried on at comparatively low temperatures, so that a large recovery of substantially undecomposed primary tar oil and ammonia is obtained. rl`he mixture of water gas and coal gas when removed from the top of the fuel column through otake 128 is comparatively cool,

' and may` be taken directly to a scrubbing and cleansing ap aratus for the removal of water, tar oils and) ammonia.

During both the air blasting operation and the water as making operation, and in particular during the gasl making operation, water or steamis s ra ed into the unburned fuel and ash at t e ottoni of the shaft by means of a coil 130, with o enings positioned below discharge openings 1n the discharging apparatus 24, 26, see Fig. 1. The water or steam is admitted to the coil 130 through a. pipe 131. The water or steam sprayed into the column portion 23 acts to quench and cool the unburned fuel and ash, and the steam formed in the quenching operation passes upwardly throu h the hot unburned fuel and ash leaving the igh temperature'zone, cooling this fuel and ash and simultaneously generatingwater gas. The water gas made by quenching in this manner during the air blasting period in the high temperature zone will be mixed with the blast gases, while during the water gas making period this water gas will mix with that ormed by blowing steam through the nostrils 18 and 39 into the high temperature zone. In order to prevent the presence of a large excess of moisture in the gas made, and to maintain a uniform quantity ofmoisture in the Water gas throughout the gas making operation, automatic regulating valves 132, Fig. 3, are used in the steam and water' connections. similar in design to the valves shown and described in the co-pending application of Loebell, Serial No. 481,195, and reference is made to said application for a detailed description' of their construction and operation. These valves 132 are positioned in the steam and water pipes leading to the regenerator vaporizing elements and to the distributing coil 130 at the bottom ofthe generator shaft, and operate in a manner such as to gradually decrease the quantity of water or steam admitted to the fuel bed durlng such water gas making period.

The mixture of unconsumed coke and ash in the bottom of the column of fuel is passed by a series of reciprocating platforms 134 positioned beneath the hoppers 26 into a hopper 136 forming a false bottom for the generator, see Fig. 3. Doors 138 in the bottom of the hopper 136 are opened at intervals and the coke and ash are discharged into a hopper 14() at the bottom ofthe shaft; The

doors 138 are closed while a discharge gate 142 is opened and the mixture of coke and ash is removed from the hopper 1210. After its removal the coke is separated from the ash and is returned to the top of the eneraorlto be recharged in admixture wit fresh The character of the gas which is made by y this process is similar in every respect to that of the gas made by the process discussed in my aforementioned application, Serial No. 481,195. The character of this gas may be accurately controlled and widely varie-d by increasing or decreasing the amount of steam used during the water gas making operation vand by varying the temperatur-cof the fuel` column. The comparatively great length,

largevolume, and uniformity of temperature gas, and removing a portion of the producer gas generated thereby upwardly through the upper portion of the column and out through the main gas oftake 129, an enriched producer gas may be made in the apparatus shown, having properties similar 1n every way to those of the gas described in my copending application, Serial No. 640,828, liled May 23, 1923. In producing this type of gas the blast air would be introduced into the fuel column `alternately through two of the three nostrils 18, 38 or 39, and a minor part of the blast gases would be'removed through the other nostril and burned in a regenerator,

while another part of the producer gas generated in the blast zone would be forced up through the fuel in the upper portion of the column to carbonize the coal therein by heat transfer therewith.

vBecause no obstruction i's offered to the passage of fuel through the shaft, and because vthe. volume of the high temperature zonevmaintained in the mid-portion of-the fuel column is large, the gas making capacity of the generator is increased considerably, and fuel canl be passed through the shaft at a rapid rate without appreciably affecting the efficiency of the process. Usually a certain proportion of the fuel is allowed to leave the shaftrunburned,` and the carbon content of the fuel column is thus kept high enough to prevent the formation of clinker durin the air blasting operation. However, the heat reactions taking place in a large portion of the fuel column throughout most of the air blasting period and all -the water gas making periodare endothermic in character, so that the material discharged from the bottom of the column may have a comparatively low carbon, or coke, and a high ash content if desired. i y

The blast air is passed through the regenerators at such a rate that it will have a predetermined degree of superheat at the time i it enters the fuel column. Substantially all of the potential heatcarried from the fuel column vby the blast gases is recovered in the refractory filling of these regenerators by burning the gas therein, and theregenerators are so designed andoperated as to prevent overheating and fusing of any part of the filling, while still effecting an eilicient heat recovery. The heat recovered in the regenerators vis returned to the fuel column in the shaft by preheating the blast air and generating and superheating the make steam, and in operation the steam isgiven the preference to obtain the highest degreeof superheat possible, while the air is used to absorb the resid` ual heat not taken up in forming steam.

The regenerator may be-so controlled `that an accurate and constant preheating ofthe air and steam andA a high thermal eiliciency is maintained throughout the operation.

The flat circumferential wall extensions 20 and hug` the outer wall of 1and 22 are constructed as an integral part of the refractory lining of the generator shaft, and the refractory material is such that it can'withstand high temperatures and fairferential passages 49 or 50 as an air blast.

inlet, and the stream of the blast air flowing beneath the-wall extension acts as a. partial protective screen against the high temperatures in the fuel adjacent' to the wall extension. The heat in the blast gases themselves is always held well below the fusing point of the refractory lining forming the IWall extension. Moreover, the location of the inlet and outlet nostrils 38 and 39 on opposite sides of theshaft and of the nostril 18 in the axial part of tion of the fuel column adjacent to the cirg cumferential blast inlet diagonally upward toward the center of the fuel column and away from the wall extension under which the blast gases are introduced.- All of these features, together with that of being able to alternate blast air between the three nostrilsvas fre-y quently as expedient, combine to permit the` .i i

continuance of the operation indefinitely the shaft has the effect of drawingthe highly heated gases developed in that porv the pointA of introduction of they without serious injury tothe refractory lin` v ing in any part of the shaft; v l, VAll of the valves in the Y-connections 51 54, 58, and 59 as well as the valves inau off the conduits which are subjectedv to high temperature gases have to be material. essentially in a refractory gate `setin slots in'- the conduit housing, and-actuated by ,a hy'- draulic or steam piston.- This type of valvev is shown and described in detail in my co-v pending application, Serial No. 481,195, and reference is hereby made to that application for a more complete description of said valve;

' When blast air or steam, is introduced into y made of refractory The type of valve used lconsists the axial dportion of the; fuel column the gases generate thereby may have a tendency to rise upwardly through the axis of the column heater. However, by using the circumferentlal gasv Oiftake 128 at thev top of the shaft wardly toward the inner wall of the carbonizing chamber during its upward passage, and 1s quite evenly distributed throughout each the central super.

v this current ,of heating gases 1s drawn outi ture of coal and coke in the fuel column in order to make a mixture of water gas and coal gas.` Coke alone may be used, in which case only blue water gas is made. The process and apparatus described above are particularly efficient and economical for use in making blue water gas or a mixture of water gas and coal gas., v

The terms radial -and radially have been used in the specification and in some of the claims to define the manner in which blast air admitted into the central vertical axis of the fuel column diverges in all directions through the fuel toward the peripheryof the column. Likewise the terms corradial and corradially have been used in the specification and in the claims to define the'maiiner in which blast air admitted peripherally into the mid-portion of the fuel column converges from passages 49 and 50' through the fuel toward the axial nostril opening 18.

The preferred form of the invention having been thusdescribed, what is claimed as new is:

1. A method of making water gas coinprising, passing fuel downwardly in an unobstructed column of circular cross section through a gas generating zone, maintaining high temperatures in said gas generating zone by periodically blasting air in a substantially radial direction through incandes' cent fuel in said zone, passing steam through incandescent fuel in the high temperature 4zone during periods following the periods of candescent fuel in the high temperature zone durinr periods following the periodsof air blasting, and passing water as thereby formed upwardly through fuel in the uper portion of the column and thereby caronizing said fuel. p

3. A method of making water gas coinprising, passing fuel downwardly in a column through a shaft generator, maintaining a high temperature water gas generating zone in the mid-portion vertically of the column by periodically blasting air in adirection substantially radially and downwardly-and alternatively in a direction substantially corradially and upwardly through incandescent fuel in said zone, between periods of air blasting introducing steam axially and periplierally into the incandescent fuel in the blast zone, and passing the hot water. gas formed upwardly through fuel in the upper 'portion of the column.

4. A method' of making water gas comprising, passing solid carbonizable fuel ldownwardly in a column through a shaft generator, maintaining a high temperature water gas generating zone in the midortion verticallyof the column by periodical yblasting air in a substantially radially downward direction through incandescent fuel in said high temperature zone, introducing steam into said high temperature zone following a period of air blasting and passing water gas 'thereby formed upwardly through. fuelin the upper portion of the column to carbonize said fuel, and after said steam run blasting air in a direction substantially coi-radially upward through the incandescent fuel in said high temperature zone, so that t-he paths of the alternating periods of the air flow are in substantially opposite directions.

5. A method of making mixed water gas and coal gas comprising, passing coal downwardly in a column through a shaft generator, maintaining a high temperature water gas generating zone in the mid-portion vertically of the column by periodically blasting air in a substantially radially downward direction through incandescent fuel in the high temperature zone, then passing steam upwardly through the incandescent fuel in the high temperature zone and thereby generating water gas, the hot water gas formed being passed upwardly through coal in the upper portion of the column whereby the coal is carbonized and .coal gas formed is carried along with the water gas.

6. The method of makingwater gas coinprising, passing coal downwardly in a column through a shaft generator, maintaining a high temperature gas making zone in the mid-portion vertically of the column by periodically blasting air in substantially radial and vertical directions through incandescent fuel in said high temperature zone between vertically spaced air inlets to and gas offtakes from said column, removing blast gases formed peripherally from the mid-portion vertically of the column, and between pe riods of air blasting introducing steam into said high temperature zone .at vertically spaced points in said column, and passing hot water gas thereby formed upwardly through coal in the upper portion of the coluilnitand out peripherally from the top ofthe s a 7. The process of making mixed water gas throng and coal gas comprising, passin coal downwardly in a column through as aft generator, maintaining a high temperature gas generating zone in the mid-portion vertically of the column by eriodically blasting air in substantially radial and corradial directions through incandescent fuel in the high temperature zone during different periods, the paths of movement of the air during successive periods bein in op osite directions, passin steam su stantial y longitudinally the incandescent fuel between lperiods of air blasting and thereby generating Water form upwardly through coal in the top of the fuel column and thereby .carbonizing the same.

' 8. A method of making combustible gas comprisi passing solid carbonizable fuel downwar y in a. continuous column successively through an upper carbonizing zone of annular cross section, thence through an unobstructed high temperature gas generating zone of circular cross section and thence through a lower waste fuel quenching zone, maintaining said high temperature gas generating zone in the mid-'portion vertically of the fuel column of introducing blast air into incandescent fuel in the'axial and peripheral portions of the said zone, removlng combustible gas generated in said mid-zone from the fuel column at points in said midzone vertically spaced fromnthe air blast inlets, passing another portion of combustible gas generated in the said gas generating zone upwardly throuh fuel in the annular carbonizing zone in irect heat interchanging relationship therewith, and removing said lastmentioned gas together with rimary volatile products distilled from the uel through the top of the fuel column.

9..A method of making combustible gas which comprises, passing solid arbonizable fuel downwardly in a. substantially unobstructed column through a shaft generator,

maintaining a high temperature gas generating zone inthe mid-portion vertically of the column by introducing blast air axially and peripherally into incandescent fuel 1n said mid-zone, carbonizing the fuelin the upper portion of the column by passing a portion of the hot combustible gas generatedin said mid-zone upwardly in direct heat transferring relationship therethrough, and remov- .inglsaid portion of combustible gas admixed with volatile products of carbonization. from the top of the fuel column.

10. A method of making combustible gas comprising, passing-fuel in an unobstructed column of circular cross section through a high temperature gas generating zone, mainta'ining gas making tem eratures throughout said zone by blasting air alternativel radially, corradially `and lo 'tudlnally t rough incandescent fuel in sai zone from and toas, and removing water gas thereby lcolumn of circular cross section through a high temperature gas generating zone, maintaining gas maki temperatures throughout said zone by blastlngair alternatively radially, corradially andlongitudinally throughi'ncandescent fuel in said zone from and toward vertically spaced points in the vertical axis and in the periphery of said high temperature zone, regenerating the sensible and otential heat of the hot blast gases removed rom the high temperature gas generating zone, and utilizing the heat thus regenerated in preheating blast airand in generating and superheating steam.

12. In a water gas generator, an upright gas generating shaft of substantially circular i cross section having an unobstructed midportion and having a fuel inlet at its top and means near its base for supporting fuel in a column in the shaft and for advancing fuel at a controlled rate therethrough, a plurality of vertically spaced axially and peripherally located nostrils in the mid-portion vertically of the shaft and circumferentialvvall extensions overlying each peripheral nostril,v whereby vertically spaced circuinzlerential gas inlets and oil'take passages are formed around the mid-portion vertically of a column of fuel in said shaft, and means operatively associated with each nostril whereby it may be used alternatively for the introduction of blast .air and of steamv into the fuel charge and for` the removal of blast gases lfrom the charge.

13. In a gas generator, an upright shaft of by air may be introduced peripherally into,

and gas removed peripherally from, the midportion vertically of a column of fuel supported in the shaft, and control valves and connections operatively associated with each p of said axial and peripheral nostrilswhereby 'zol circular cross section having a substantially they may be used interchangeably as air and steam inlets and as gas ofitakes.

14. In a gas generator, an upright gas generating shaft, a fuel charging device at the top of the shaft, an ash discharging device at the bottom of the shaft, a conduit mounted within the upper portion of the shaft with one end opening into the mid-portion vertically of the shaft adjacent the longitudinal axis of the shaft, two circumferential wall extensions formed in the inner peri hery of the vertical mid-portion of the sha each of said extensions being spaced vertically and laterally a substantial distance from the other, said shaft having a nostril opening into it directly beneath each of said wall extensions, and means coacting with each of said nostrils and with said axially mounted conduit whereby said conduit and each of said nostrils may be used interchangeably for the introduction of air and steam into the shaft and for the removal of gases from the shaft. 15. In a gas generator, an upright gas generating shaft having means near its base for supporting fuel in a column therein and for advancing fuel therethrough, a steam-jacketed conduit mounted in the upper portion of the shaft along the longitudinal axis thereof and arranged to discharge blast air and steam axially into the mid-portion vertically of a column of fuel inthe shaft, two vertically spacedinostril o enings in the walls of the shaft in the mi -section vertically thereof, and a pair of heat regenerators each having interchangeable air blast, steam and exhaust gas connections with each of said nostrils and with the jacketed conduit. y

16. in a gas generator, an upright gas generating shaft of circular cross section having means in its base whereby fuel is supported in a column therein and advanced at `a. controlled rate therethrough, two vertically spacedl circumferential wall extensions in the midortion vertically of the shaft, each forming with the periphery of a column of fuel suppkorted therein a circumferential passage t rough which gases may be introduced into and removed from the fuel charge, a nostril opening into the shaft'immediatly beneath each of said wall extensions and communicating with said circumferential passages, a conduit mounted axially in the upper portion of the shaft and opening into the mid-portion vertically of the shaft in the longitudinal axis thereof, valved connections whereby each of said circumferentiel passages and said axial conduit may be employed alternatively as blast air and steam inlets and as blast gas oltalres, and a circumferential rich gas odtake mounted in the' top of the shaft,

li. i method of melting combustible which comprises, passing solid combustible fuel in a suhstantiy unobgases through the fuel toward one of said outlets, removing the last-named portion of the combustible gas admixed with volatile products of carbonization from the top of the fuel column, and alternating the points of introduction of the air and the outlets for the' blast gasesto control the distribution of temperature within the said gas' generating zone.

18. A method of making combustible gas comprising, passing solid fuel in an unobstructed column through a high temperature gas-generating zone, maintaining gas-maliing temperatures through said zone by blasting air alternately radially and corradially through incandescent solid fuel in said zone from and toward vertically-spaced points re-- spectively in the vertical axis and 1n the periphery of the said high temperature zone, passing superheated steam into and upwardly through the said high temperature blast zone, generating and superheatin steam adjacent theupper portion of the uel column and out of direct contact with combustible gases, and subsequently introducing the lastnamed steam into the upper portion of the saidhigh temperature blast zone.

19. In a gas generator, an upright as generating shaft having means near its ase for supporting fuel in a column therein. and for advancing fuel therethrough, a steam-jacketed conduit mounted within the upper portion of the shaft along thelongitudinal axis thereof, means operatively associated with the said conduit for selectively discharging blast air and steam through said conduit into the midortion vertically of a column of fuel in t e shaft, a water conduit leading fromoutside the shaft to the said jacket, means connecting the upper portion of the jacket withthe said first-mentioned conduit,

two vertically spaced nostrils in the walls of the shaft at theV mid-section vertically thereof, and a pair of heat regenerators each having interchangeable air blast,steam and exhaustga's connection with each of the said nostrilsand with the jacketed conduit, and valved means for directly connecting together thevrespective air blast and exhaust gas connections of each regenerator.

In testimony whereof l a my si ature.

HENRY 0.' LOEBELL.

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